Method and apparatus for transmitting user input from a sink device to a source device in a Wi-Fi direct communication system

ABSTRACT

A method of performing communication between a sink device and a source device in a Wi-Fi direct network is provided. The method includes receiving a user&#39;s input, on a sink device, for controlling audio/video (AV) data received from the source device, generating a message for controlling the AV data based on the user&#39;s input, and transmitting the message to the source device through a Wi-Fi direct link.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation Application of U.S. application Ser.No. 13/979,802, filed Jul. 15, 2013, which is a National Stage ofInternational Application No. PCT/KR2012/000341, filed on Jan. 13, 2012,and claims priority from U.S. Provisional Patent Application No.61/432,779, filed on Jan. 14, 2011, the disclosures of which areincorporated herein in their entirety by reference.

BACKGROUND 1. Field

Exemplary embodiments relate to a method and apparatus for transmittinga user's input from a sink device to a source device in a Wi-Fi directcommunication scheme.

2. Related Art

Unlike existing Wi-Fi communication schemes, a Wi-Fi directcommunication scheme is a network suggested by a Wi-Fi alliance, whereWi-Fi devices are connected in a peer-to-peer scheme even though theWi-Fi devices do not participate in a home network, an office network,and a hot spot network.

In the Wi-Fi direct communication scheme, a sink device is merely adevice that displays audio/video (AV) data, and cannot receive a user'sinput for controlling the AV data. Hence, the user has to input acommand to a source device in order to control the AV data.

SUMMARY

Exemplary embodiments provide a method to address an inconveniencecaused when a user's input for controlling audio/video (AV) datatransmitted from a source device to a sink device always needs to beinput to the source device.

According to an aspect of an exemplary embodiment, there is provided amethod of performing communication between a source device and a sinkdevice in a Wi-Fi direct network, including: receiving a user's input,by the sink device, for controlling audio/video (AV) data, andtransmitting the received user's input to the source device.

According to an aspect of another exemplary embodiment, there isprovided a method of performing communication between a sink device anda source device in a Wi-Fi direct network, including: receiving a user'sinput, by the sink device, for controlling audio/video (AV) datareceived from the source device; generating a message for controllingthe AV data based on the user's input; and transmitting the message tothe source device through a Wi-Fi direct link.

The method may further include: providing the source device withinformation on whether the sink device generates the message andprovides the message to the source device; and transmitting parameterinformation for processing the message.

The parameter information may be included in a real time serviceprotocol (RTSP) message.

The providing and the transmitting may be performed in a capabilitynegotiation procedure.

Based on the user's input, the message for controlling the AV data mayinclude information corresponding to at least one of a coordinate, amagnifying power of zooming, a scrolling amount, a rotation amount, andASCII code.

Based on the user's input, the message for controlling the AV data mayinclude information corresponding to an interface type of a humaninterface device (HID).

Based on the user's input, the message for controlling the AV data mayinclude information corresponding to a type of a human interface device(HID).

According to an aspect of another exemplary embodiment, there isprovided a method of performing communication between a source deviceand a sink device in a Wi-Fi direct network, including: receiving amessage, by the source device, generated in the sink device based on auser's input to the sink device; and controlling audio/video (AV) databased on the received message in the source device, wherein the messageis received through a Wi-Fi direct link.

The method may further include: requesting the sink device forinformation on whether the sink device generates the message andprovides the message to the source device; and receiving parameterinformation for processing the message.

The parameter information may be included in a real time serviceprotocol (RTSP).

According to an aspect of another exemplary embodiment, there isprovided a communication device for performing communication in a Wi-Fidirect network, including: a user input reception unit that receives auser's input for controlling audio/video (AV) data received from asource device; a message generation unit that generates a message forcontrolling the AV data based on the user's input; and a messagetransmission unit that transmits the message to the source devicethrough a Wi-Fi direct link.

The communication device may further include: a capability informationproviding unit that provides the source device with information onwhether the sink device generates the message and provides the messageto the source device; and a parameter information providing unit thatprovides parameter information needed for processing the message to thesource device.

The parameter information may be included in a real time serviceprotocol (RTSP) message.

Based on the user's input, the message for controlling the AV data mayinclude information corresponding to at least one of a coordinate, amagnifying power of zooming, a scrolling amount, a rotation amount, andASCII code.

Based on the user's input, the message for controlling the AV data mayinclude information corresponding to an interface type of a humaninterface device (HID).

Based on the user's input, the message for controlling the AV data mayinclude information corresponding to a type of a human interface device(HID).

According to an aspect of another exemplary embodiment, there isprovided a communication device for performing communication in a Wi-Fidirect network, including: a message reception unit that receives amessage generated in a sink device based on a user's input from the sinkdevice; and a data controller that controls audio/video (AV) data basedon the received message in the source device, wherein the message isreceived through a Wi-Fi direct link.

The communication device may further include: a capability informationrequest unit that requests the sink device for information on whetherthe sink device generates the message and provides the message to thesource device; and a parameter information reception unit that receivesparameter information needed for processing the message.

The parameter information may be included in a real time serviceprotocol (RTSP). According to an aspect of another exemplary embodiment,there is provided a method of performing communication between a sinkdevice and a source device in a Wi-Fi direct network, the methodincluding: generating a message for controlling audio/video (AV) datareceived from the source device based on a user's input to the sinkdevice; and transmitting the message from the sink device to the sourcedevice through a Wi-Fi direct link.

The method may also include providing the source device with informationcorresponding to whether the sink device has a capability to control theAV data received from the source device; and transmitting parameterinformation for processing the message.

Accordingly, an inconvenience caused when a user's input for controllingaudio/video (AV) data always needs to be input to a source device may beaddressed by receiving the user's input for controlling AV data directlyat a sink device in a Wi-Fi direct network, and transmitting thereceived user's input to the source device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conceptual diagram illustrating a communication schemebetween a sink device and a source device, according to an exemplaryembodiment;

FIG. 2 shows a flowchart illustrating a procedure of performing acommunication between the sink device and the source device, accordingto an exemplary;

FIG. 3 shows a flowchart illustrating a procedure of performing acommunication between a source device and a sink device, according toanother exemplary embodiment;

FIG. 4 shows a block diagram illustrating a structure of the sourcedevice and the sink device, according to an exemplary embodiment;

FIG. 5 shows a structure of a message transmitted from the sink deviceto the source device, according to an exemplary embodiment;

FIG. 6 shows a table illustrating an input category, according to anexemplary embodiment;

FIG. 7 shows a format of a generic input body, according to an exemplaryembodiment;

FIG. 8 shows a table illustrating types of a user's input of a genericinput category, according to an exemplary embodiment;

FIG. 9 shows a format of an information element according to a user'smouse input, according to an exemplary embodiment;

FIG. 10 shows a format of an information element according to a user'skeyboard input, according to an exemplary embodiment;

FIG. 11 shows a format of an information element according to a user'szoom input, according to an exemplary embodiment;

FIG. 12 shows a format of an information element according to a user'sscroll input, according to an exemplary embodiment;

FIG. 13 shows a format of an information element according to a user'srotation input, according to an exemplary embodiment;

FIG. 14 shows a body format of a human interface device class (HIDC,)according to an exemplary embodiment;

FIG. 15 shows a table illustrating a type of a human interface device(HID) according to an exemplary embodiment;

FIG. 16 shows a table illustrating a type of an HID according to anexemplary embodiment;

FIG. 17 shows a signal flowchart of a communication between the sourcedevice and the sink device, according to an exemplary embodiment;

FIG. 18 shows a format of a Wi-Fi display (WFD) information elementaccording to an exemplary embodiment;

FIG. 19 shows a format of a WFD subelement according to an exemplaryembodiment; and

FIG. 20 shows a table illustrating a WFD subelement ID according to anexemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments will now be described more fully with reference tothe accompanying drawings. Like reference numerals in the drawingsdenote like elements, and thus their description will be omitted. Thesize of each component of drawings may be exaggerated for clarity ofdescription.

FIG. 1 is a conceptual diagram illustrating a communication schemebetween a sink device and a source device according to an exemplaryembodiment.

A Wi-Fi display (WFD) is a communication scheme where display devicescommunicate based on a Wi-Fi direct communication standard.

A source device is a device that provides data, and a sink device is adevice that receives data. In the Wi-Fi direct communication scheme, thesource device and the sink device are determined in the capabilitynegotiation operation according to the capability of a device. Inparticular, the sink device may include a device that displaysaudio/video (AV) data.

According to an exemplary embodiment, the sink device receives a user'sinput for controlling AV data, and a user may directly input a commandfor controlling AV data through a scheme that transmits informationcorresponding to the user's input received by the sink device to thesource device.

The sink device may provide information corresponding to the inputreceived from the user to the source device via a user input backchannel (UIBC).

Information corresponding to the user's input for controlling AV datamay be of various types, such as a mouse input (coordinates), a keyboardinput, a zoom input, a scroll input, and a rotation input.

FIG. 2 shows a flowchart illustrating a procedure of performing acommunication between the sink device and the source device in a Wi-Fidirect network, according to an exemplary embodiment.

In operation 201, the sink device receives a user's input forcontrolling AV data. Before receiving the user's input, the sink devicemay transmit information on whether a function of receiving the user'sinput and transmitting the user's input to the source device issupported. The sink device may transmit parameter information needed forprocessing the user's input along with the information on whether thefunction of transmitting the user's input to the source device issupported.

The operation of transmitting the parameter information needed forprocessing the user's input along with the function of transmitting theuser's input to the source device via the UIBC (User Input Back Channel)may be performed in a capability negotiation procedure or a servicediscovery procedure.

Furthermore, the parameter information may be included in a real timestreaming protocol (RTSP).

In operation 202, the sink device generates a message based on theuser's input. When the message is generated based on the user's input,the message is generated according to the structure of FIG. 5, whichwill be described in detail below with reference to FIG. 5.

When the message based on the user's input is generated, interface typeinformation of a human interface device (HID) may be included in themessage, and type information of the HID may be included in the message,as described later in detail with reference to FIGS. 15 and 16.

In operation 203, the sink device transmits the message to the sourcedevice through the Wi-Fi direct link. The source device communicateswith the sink device through the WFD scheme, and thus the source deviceis connected to the sink device through the Wi-Fi direct link.Furthermore, the sink device may provide information corresponding tothe input received from the user to the source device in the form of amessage through the UIBC connected to the source device.

FIG. 3 shows a procedure of performing a communication between a sourcedevice and a sink device, according to another exemplary embodiment.

In operation 301, the source device receives a message generated in thesink device based on the user's input. Before receiving the message, thesource device may request the sink device for information on whether afunction of transmitting the user's input received by the sink device tothe source device is supported. The source device may receive parameterinformation needed for processing the user's input in response to therequest of the information on whether the function of transmitting theuser's input to the source device is supported.

The operation of receiving the parameter information needed forprocessing the user's input and the requesting for information onwhether a function of transmitting the user's input from the sink deviceto the source device may be performed in the capability negotiationprocedure or the service discovery procedure.

Furthermore, the parameter information may be included in the RTSP.

In operation 302, the source device controls AV data based on thereceived message which is generated by the sink device. The sourcedevice and sink device may control AV data through a device thatperforms an input through a pointer, such as a mouse, a touch pad, and atouch panel, or may input an ASCII code value as in a keyboard.Furthermore, the AV data may be AV data, which is streaming in the sinkdevice. AV data may be controlled by inputting zoom magnification, ascroll amount, and a rotation amount in the streaming AV data.

FIG. 4 shows a structure of a source device 401 and a sink device 411according to an exemplary embodiment.

The source device 401 includes a capability information request unit402, a parameter information reception unit 403, a message receptionunit 404, and a data controller 405.

The capability information request unit 402 requests for information onwhether the sink device 411 linked by a Wi-Fi direct link provides afunction of receiving a user's input and transmitting the user's inputto the source device 401 through the set UIBC.

The parameter information reception unit 403 receives, from the sinkdevice 411, a parameter for processing a message generated based on theuser's input.

The message reception unit 404 receives the message generated in thesink device 411 based on the user's input.

The data controller 405 controls AV data based on the message generatedfrom the user's input received from the sink device 411.

The sink device 411 includes a capability information providing unit412, a parameter information providing unit 413, a user's inputreception unit 414, a message generation unit 415 and a messagetransmission unit 416.

In response to the request of the source device 401, the capabilityinformation providing unit 412 provides information on whether the sinkdevice 411 linked by the Wi-Fi direct link provides the function ofreceiving the user's input and transmitting the user's input to thesource device through the set UIBC.

The parameter information providing unit 413 provides to the sourcedevice 401 parameter information needed for processing the messagegenerated based on the user's input to the source device 401.

The user's input reception unit 414 receives a user's input to controlAV data.

The message generation unit 415 generates a message based on the user'sinput in order to transmit the user's input to the source device 401through the UIBC.

The message transmission unit 416 transmits the message generated basedon the user's input to the source device 401 through the UIBC.

FIG. 5 shows a structure of a message transmitted from the sink deviceto the source device, according to an exemplary embodiment.

According to an exemplary embodiment, a version field represents aversion of a protocol and has a 2-bit size.

According to an exemplary embodiment, a T field is an abbreviation of atime stamp, represents whether a time stamp field exists, and has a1-bit size. The time stamp field is selective, and when T is 0, itindicates that the time stamp field does not exist and when T is not 0,it indicates that the time stamp field exists.

According to an exemplary embodiment, a reservation field exists inpreparation of a situation when the received field is needed, and has an8-bit size. The reservation field is displayed as 0s.

According to an exemplary embodiment, a length field represents a lengthof an entire message and has an 8-bit size.

According to an exemplary embodiment, an input category field shows acategory of an input transmitted through a message, and has a 4-bitsize. The input category is divided into a generic input and an inputabout a HID. The input device will be described later in detail withreference to FIG. 6.

According to an exemplary embodiment, the time stamp field is anoptional field, and displays a time stamp of a real time protocol (RTP)of a frame displayed by the application of the user's input. Accordingto an exemplary embodiment, the time stamp field has a 16-bit size.

According to an exemplary embodiment, the input body field is a fieldincluding information corresponding to the user's input. The contentabout a generic input or an HID input is inserted into the input bodyfield.

FIG. 6 shows a table illustrating an input category, according to anexemplary embodiment.

According to an exemplary embodiment, the input category is divided intoinformation on a generic input and information on a human interfacedevice class (HIDC), as described in FIG. 5. When the input category isdisplayed as 0, the message of FIG. 5 includes an information elementabout a generic input, and when the input category is displayed as 1,the message includes an information element corresponding to the HIDC.

According to an exemplary embodiment, the generic input includesinformation such as a movement, click, touch, zoom magnification, scrollamount, and rotation amount of a mouse, a touch pad, etc.

According to an exemplary embodiment, the user interface deviceinformation element includes information corresponding to a standard(HID interface type) through which the user's device has been connectedto the sink device, and an input device (HID type) to which the sinkdevice has been connected.

FIG. 7 shows a format of a generic input body according to an exemplaryembodiment.

According to an exemplary embodiment, the format of the generic inputbody includes a generic IE ID field, a length field, and a descriptionfield.

According to an exemplary embodiment, the generic IE ID field is a fieldfor distinguishing types of a user's input in a generic input category,as described later in detail with reference to FIG. 8.

According to an exemplary embodiment, the length field represents alength of the entire field and has a 2-octet size.

According to an exemplary embodiment, the description field representsthe actual content of the user's input. That is, the actual content ofthe user's input, such as coordinates, number, zoom magnification,scroll amount, and rotation amount, is displayed. The content disclosedin the description field will be described in detail with reference toFIGS. 9 to 13.

FIG. 8 shows a table illustrating types of a user's input of a genericinput category, according to an exemplary embodiment.

FIG. 8 illustrates the types of the user's input which may be disclosedin the generic IE ID field of the input body format.

According to an exemplary embodiment, Down refers to an operation ofpressing a mouse button or key, and Up refers to an operation ofreleasing the mouse button or key. The message may be transmitted forthe user's input of various forms, such as a click of a left or rightbutton of a mouse, and a movement, zoom, scroll, rotation, etc. of amouse or a touch pad.

Furthermore, the generic IE ID may be omitted as necessary.

FIG. 9 shows an information element according to a user's mouse inputaccording to an exemplary embodiment.

FIG. 9 illustrates a case where the sink device receives a user's inputthrough a mouse in order to control AV data, and the content of FIG. 9may be written in the description field of the generic input body ofFIG. 7.

According to an exemplary embodiment, the number field of the pointerrepresents the number of pointers. For example, a plurality of pointersmay be provided. In the case of the mouse, there is one pointer.However, in the case of a touch pad, a multi-touch is supported, andthus two or more points may be provided. Hence, when there is aplurality of pointers, information for each pointer may be written usinga construction (expression) using a “For loop” coding scheme. A “Forloop” coding scheme is well known to those skilled in the art, and thusthe detailed description thereof is omitted here.

According to an exemplary embodiment, the pointer ID field represents anID for distinguishing each pointer when there is a plurality ofpointers.

According to an exemplary embodiment, x-coordinate and y-coordinatefields respectively represent the x-coordinate and y-coordinate of eachpointer, which may be normalized according to the resolution of thevideo stream.

FIG. 10 shows an information element of a user's keyboard inputaccording to an exemplary embodiment.

FIG. 10 illustrates a case where the sink device receives a user's inputthrough a keyboard to control AV data, and the content of FIG. 10 may bewritten in the description field of the generic input body of FIG. 7.

According to an exemplary embodiment, a total of two key code fields areprovided because there is a case where two keys may need to be input atone time as in a shortcut key. According to an exemplary embodiment,each key code field has a 2-octet size, and an input key is indicated byASCII code. Generally, the ASCII code is indicated by a size less than 1byte, and the remaining 1 byte is a byte reserved for compatibility whenASCII code is changed later.

Furthermore, when only one key is input, Key Code II field is indicatedas 0.

FIG. 11 shows an information element according to a user's zoom input,according to an exemplary embodiment.

According to an exemplary embodiment, x-coordinate field andy-coordinate fields respectively indicate x and y coordinates referredto for a zoom operation. The x and y coordinates may be normalizedaccording to the resolution of the video stream.

According to an exemplary embodiment, the integer times to zoom fieldrepresents an integer part of the magnifying power of the zoomoperation. For example, if the zoom magnifying power is 2.5, “2”, whichis the integer part of 2.5, is displayed in the integer part of the zoommagnifying power. Furthermore, the zoom operation is performed only asmagnification, and thus only an unsigned integer is displayed.

According to an exemplary embodiment, the fraction times to zoom fieldrepresents a decimal part of the magnifying power of the zoom operation.For example, if the zoom magnifying power is 2.5, “0.5” which is thedecimal part of 2.5 is displayed in the decimal part of the zoommagnifying power.

FIG. 12 shows an information element according to a user's scroll inputaccording to an exemplary embodiment.

According to an exemplary embodiment, the amount to scroll fielddisplays the number of pixels changed according to the scroll accordingto the resolution.

Furthermore, according to an exemplary embodiment, the scroll operationmay be performed horizontally and vertically, and in a specifieddirection (left and right or upward and downward), and thus is indicatedby a signed integer. For example, a negative integer represents a rightor upward scroll operation, and a positive integer represents a left ordownward scroll operation is displayed.

FIG. 13 shows an information element according to a user's rotationinput according to an exemplary embodiment.

According to an exemplary embodiment, the integer portion of rotationamount field represents an integer part of the rotation amount. Therotation amount is indicated in radian units. The rotation operationalso has a direction (clockwise or counterclockwise direction), and thusis indicated by a signed integer. For example, in the case of a negativeinteger, a clockwise rotation is displayed, and in the case of apositive integer, a counterclockwise rotation is displayed.

According to an exemplary embodiment, the fraction portion of rotationamount represents a fraction part of the magnifying power of the zoomoperation.

FIG. 14 shows a body format of an HIDC, according to an exemplaryembodiment.

According to an exemplary embodiment, the body format of the HIDCincludes HID interface type, HID type, usage, length, and HIDC valuefields.

According to an exemplary embodiment, the HID interface type fieldrepresents a connection type of the HID interface, as described later indetail with reference to FIG. 15.

According to an exemplary embodiment, the HID type field represents thetypes of the HID, as described later in detail with reference to FIG.16.

According to an exemplary embodiment, the usage field is a fieldcorresponding to the HIDC value, and displays the usage of the contentwritten in the HIDC value field, such as whether the HIDC value is usedin the HID input report or is used as a HID report descriptor.

According to an exemplary embodiment, the length field displays thelength of the entire message and has a 2-octet size.

According to an exemplary embodiment, the HIDC value field displayscontent on the HID input report or description on the HID input, and thesize of the HIDC value field is variable.

FIG. 15 shows a table illustrating a type of an HID according to anexemplary embodiment.

According to an exemplary embodiment, the connection type between thesink device and the HID device is illustrated by each value. Theconnection types may include an infrared type, a universal serial bus(USB) type, a Bluetooth type, a ZigBee type and a Wi-Fi type. Theconnections types are obvious to those skilled in the art, and thus thedetailed description thereof is omitted here.

Furthermore, a connection type that is later newly used may be matchedwith value 5-254 so as to be used to identify a new type of connection,and the vendor specific HID interface may be used by defining a newconnection type that that is not defined by the vendor.

FIG. 16 shows a table illustrating a type of an HID according to anexemplary embodiment.

According to an exemplary embodiment, FIG. 16 shows HID interface types,i.e., types of an input device connected to the sink device. Someexamples of the HID are a keyboard and a mouse, and in the case of atouch pad or a touch panel, there is a single touch and a multi touch.Furthermore, there are other examples, such as a joystick, a camera, agesture, and a remote controller.

Furthermore, a new input device may be matched with the value 5-254 soas to be used to identify the new input device.

FIG. 17 shows a signal flowchart of a communication between the sourcedevice and the sink device, according to an exemplary embodiment.

In operation 1701, the source device requests information on whether aUIBC capability is supported from the sink device. The UIBC is a channelfor transmitting a user's input that is set based on a Wi-Fi directscheme in order to transmit to the source device informationcorresponding to the input that the sink device receives from the user.

In operation 1702, in response the request of the information on whetherthe UIBC capability is supported, the sink device transmits informationon whether the UIBC capability is supported.

In operation 1703, if a coordinate-related input is received, the sinkdevice generates a message according to the format of FIG. 5, andtransmits the message.

In operation 1704, in response the transmission of the message generatedbased on the user's input of the sink device, the source devicetransmits a message reception confirmation signal to the sink device.

Operation 1705 is similar to operation 1703, and a case where the sinkdevice receives an input corresponding to text data from the user isillustrated.

In operation 1706, the source device transmits a message receptionconfirmation signal as in operation 1704.

Data that may be included in the user's input message in each operationmay further include at least one of the rotation amount information andthe magnifying power of the zoom information as described above.

FIG. 18 shows a WFD information element according to an exemplaryembodiment.

According to an exemplary embodiment, the WFD information elementrepresents a format of a frame that receives basic information, such asa device type and state. The probe request frame or probe response framemay also be written according to the format of the WFD informationelement. The request and response of information on whether the function(e.g., UIBC) of transmitting an input received from the user from thesink device to the source device is transmitted using the WFDinformation element.

According to an exemplary embodiment, the WFD IE includes an element IDfield, a length field, an organization unique identifier (OUI) field, anOUI type field, and a WFD subelement field. According to an exemplaryembodiment, the element ID field, the length field, the OUI field, andOUI type field have 1, 1, 3 and 1 octet sizes, respectively, and thesize of the WFD subelement field is variable.

According to an exemplary embodiment, the element ID field is a fieldused when the vendor desires to make functions that are not defined inthe IEEE 802.11 standard, and the length field represents the entirelength of the WFD information element.

According to an exemplary embodiment, the OUI field is a uniqueidentifier that distinguishes each vendor.

According to an exemplary embodiment, the OUI type field represents aversion of the WFD information element.

According to an exemplary embodiment, the content written simply in theWFD information element is not sufficient for the WFD subelement field,and thus content indicating detailed device information is included, andthe content included in the WFD subelement will be described withreference to FIG. 19.

Some of the WFD information elements may be omitted as necessary.

FIG. 19 shows a general format of a WFD subelement according to anexemplary embodiment.

According to an exemplary embodiment, the WFD subelement includessubelement ID, length, and subelement body fields. According to anexemplary embodiment, the subelement ID and length fields haverespectively one octet size, and the size of the subelement body fieldis variable.

According to an exemplary embodiment, the subelement ID displays thetype of the WFD subelement, which will be described in detail withreference to FIG. 20.

According to an exemplary embodiment, the length field represents theentire length of the WFD subelement.

According to an exemplary embodiment, the subelement body field showsdetails of the subelement.

Some of the WFD subelements may be omitted as is necessary.

FIG. 20 shows a table illustrating a WFD subelement ID according to anexemplary embodiment.

According to an exemplary embodiment, the WFD device information meansinformation on the WFD device. The information corresponding to the UIBCcapability may also be included in the WFD device information field.

The status of the present embodiment indicates the status information ofthe device, and the display EDID represents the type of data fortransmitting display information of the device. Furthermore, the coupledsink information of the present embodiment shows whether connected toanother device.

The remaining subelement ID is about the Codec, device capability andaddress which may be easily understood by those skilled in the art, andthus the detail description thereof is omitted here.

Some of the subelement IDs may be omitted as necessary.

Exemplary embodiments may also be embodied as computer-readable codes ona computer-readable recording medium. The computer-readable recordingmedium is any data storage device that can store data which can bethereafter read by a computer system and executed by using a processor.Examples of the computer-readable recording medium include read-onlymemory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes,floppy disks, optical data storage devices, etc. The computer-readablerecording medium can also be distributed over network-coupled computersystems so that the computer-readable code is stored and executed in adistributed fashion.

While exemplary embodiments have been particularly shown and describedwith reference to the drawings, it will be understood by those ofordinary skill in the art that various changes in form and details maybe made therein without departing from the spirit and scope of theinventive concept as defined by the following claims.

What is claimed is:
 1. A method of performing communication between a sink device and a source device in a peer to peer network, the method comprising: receiving a user's input data, by the sink device, for controlling the AV data received from the source device; generating a message for controlling the AV data based on the user's input data; and transmitting the message for controlling the AV data to the source device such that the AV data is controlled by the source device based on the message.
 2. The method of claim 1, wherein the message for controlling the AV data comprises input category information indicating a category of the user's input data transmitted through the message.
 3. The method of claim 2, wherein the category of the user's input data comprises a generic input category and a Human Interface Device Class (HIDC) category.
 4. The method of claim 3, wherein the message comprises input type information for distinguishing types of the user's input data, when the input category is the generic input category.
 5. The method of claim 4, wherein the input type information comprises information regarding at least one of a mouse input type, a keyboard input type, a touch input type, a zoom input type, a scroll input type and a rotation input type.
 6. The method of claim 5, wherein the message comprises information corresponding to at least one of the number of pointer, a coordinate, a magnifying power of zooming, a scrolling amount, a rotation amount, and ASCII code.
 7. The method of claim 3, wherein the message comprises Human Interface Device (HID) interface type information indicating a connection type of the HID interface and HID type information indicating type of the HID, when the input category is the HIDC input category.
 8. The method of claim 7, wherein the connection type comprises at least one of an infrared type, a universal serial bus (USB) type, a Bluetooth type, a ZigBee type and a Wi-Fi type.
 9. The method of claim 5, wherein the HID comprises at least one of a keyboard, a mouse, a single touch device, a multi touch device, a joystick, a camera, a gesture, and a remote controller.
 10. The method of claim 1, wherein the message for controlling the AV data comprises at least one of a version field indicating a version of a protocol, an input category field indicating a category of the user's input data transmitted through the message, an input body field comprising information corresponding to the user's input data, a time stamp field indicating a time stamp of a real time protocol (RTP), a reservation field, a length field represents a length of an entire message.
 11. A communication device for performing communication in a peer to peer network, the communication device comprising: a processor which is configured to receive a user's input data for controlling audio/video (AV) data received from a source device, and generate a message for controlling the AV data based on the user's input data; a transmitter which is configured to transmit the message for controlling the AV data to the source device such that the AV data is controlled by the source device based on the message.
 12. The device of claim 11, wherein the message for controlling the AV data comprises input category information indicating a category of the user's input data transmitted through the message.
 13. The device of claim 12, wherein the category of the user's input data comprises a generic input category and a Human Interface Device Class (HIDC) category.
 14. The device of claim 13, wherein the message comprises input type information for distinguishing types of the user's input data, when the input category is the generic input category.
 15. The device of claim 14, wherein the input type information comprises information regarding at least one of a mouse input type, a keyboard input type, a touch input type, a zoom input type, a scroll input type and a rotation input type.
 16. The device of claim 15, wherein the message comprises information corresponding to at least one of the number of pointer, a coordinate, a magnifying power of zooming, a scrolling amount, a rotation amount, and ASCII code.
 17. The device of claim 13, wherein the message comprises Human Interface Device (HID) interface type information indicating a connection type of the HID interface and HID type information indicating type of the HID, when the input category is the HIDC input category.
 18. The device of claim 17, wherein the connection type comprises at least one of an infrared type, a universal serial bus (USB) type, a Bluetooth type, a ZigBee type and an Wi-Fi type.
 19. The device of claim 15, wherein the HID comprises at least one of a keyboard, a mouse, a single touch device, a multi touch device, a joystick, a camera, a gesture, and a remote controller.
 20. The device of claim 11, wherein the message for controlling the AV data comprises at least one of a version field indicating a version of a protocol, an input category field indicating a category of the user's input data transmitted through the message, an input body field comprising information corresponding to the user's input data, a time stamp field indicating a time stamp of a real time protocol (RTP), a reservation field, a length field represents a length of an entire message.
 21. A method of performing communication between a source device and a sink device in a peer to peer network, the method comprising: receiving a message, by the source device, generated in the sink device based on a user's input data received by the sink device; controlling audio/video (AV) data based on the received message in the source device; transmitting the AV data to the sink device.
 22. A communication device for performing communication in a peer to peer network, the communication device comprising: a receiver which is configured to receive a message generated in a sink device based on a user's input data received by the sink device; and a processor which is configured to control audio/video (AV) data based on the received message in the source device, a transmitter which is configured to transmitting the AV data to the sink device. 